Originally from Wailuku, Maui, Derrick currently resides in San Francisco, and is in the final year of his Civil Engineering degree at San Francisco State University.  With an interest in geotechnical engineering, Derrick hopes to gain work experience before returning to obtain a graduate degree.  In his free time, Derrick enjoys diving and baseball, and loves being back home, surrounded by the beautiful nature of Hawai‘i.

Evaluation of Dynamic Wind Loading on Rigid vs. Non-Rigid Baffle Materials
Project Site: Air Force Research Laboratory
Mentor: Stacie Williams

Project Abstract:

A light baffle will be introduced to the Advanced Electro Optical System (AEOS) Telescope, and the increase in surface area is expected to amplify negative effects of dynamic wind loading on the telescope structure.  Dynamic wind loading—fluctuations in wind pressure—contributes to degradation of telescope images due to pointing and focus errors.  In order to minimize these effects in baffle design, an analysis was conducted to determine performance differences between rigid vs non-rigid baffle materials in hopes of reducing wind loading and jitter transmission to the primary telescope structure induced by the baffle.  To quantify this, a 6’ frame was constructed to simulate the AEOS truss while ply and tarp baffles measuring 3’ by 3’ were fitted to the frame through strap attachments at each corner.  Piezoelectric force transducers were used to measure the change in force of each strap with respect to time, and power spectral density plots were used to evaluate performance of both baffle materials.  Flexibility of the tarp baffle is expected to dampen high frequency transmission to the telescope allowing the mount control system to reject remaining wind load effects.  On the other hand, due to the rigidity of ply material, its power spectral density plot is suspected to have a less pronounced roll off of frequencies above 2 Hz—frequencies that cannot be rejected by the telescopes active control loop—and is therefore more likely to negatively impact image quality.